__adjust.c

来自「KPIT GNU Tools is a set of GNU developme」· C语言 代码 · 共 45 行

/*
 * return (*acc) scaled by 10**dexp.
 */

#include <_ansi.h>
#include <reent.h>
#include "std.h"

#define abs(x) (((x) < 0) ? -(x) : (x))

double
_DEFUN (__adjust, (ptr, acc, dexp, sign),
	struct _reent *ptr _AND
	double *acc _AND
	int dexp _AND
	int sign)
     /* *acc	the 64 bit accumulator */
     /* dexp	decimal exponent       */
     /* sign	sign flag   	       */
{
  double r;

  if (dexp > MAXE)
    {
      ptr->_errno = ERANGE;
      return (sign) ? -HUGE_VAL : HUGE_VAL;
    }
  else if (dexp < MINE)
    {
      ptr->_errno = ERANGE;
      return 0.0;
    }

  r = *acc;
  if (sign)
    r = -r;
  if (dexp == 0)
    return r;

  if (dexp < 0)
    return r / __exp10 (abs (dexp));
  else
    return r * __exp10 (dexp);
}